title: Bradykinin preconditioning modulates aquaporin-4 expression after spinal cord ischemic injury in rats.
abstract: The study investigated whether bradykinin (BK) preconditioning could regulate the expression of aquaporin-4 (AQP4) using an in vivo transient spinal cord ischemia model in rats. BK was infused continuously via the left femoral artery with infusion pump for 15 min (10 microg/kg/min) then we induced ischemia for 20 min and reperfusion for 24 and 72 h respectively. The results demonstrated that the central part of the white matter exhibited loss of perivascular AQP4 and showed a partial recovery toward 72 h of reperfusion. The border zone of white matter was different from the central part of the white matter by showing no loss of perivascular AQP4 at 24 h of reperfusion but rather a slight increase. BK significantly reduced the expression level of AQP4 protein in the white matter, but it had none of this effect in the gray matter region at 72 h post-reperfusion. There was no difference in AQP4 protein levels between BK group and control group at the two above-mentioned spinal cord regions at 24 h after reperfusion. In addition, the changes in AQP4 protein induced by BK preconditioning were obvious at 72 h after reperfusion, which were accompanied by a reduction of spinal cord edema. Our results demonstrated that the expression of AQP4 protein after spinal cord ischemia/reperfusion was region-specific, time-dependent and also indicated that the attenuation of AQP4 expression induced by BK could be one of the important molecular mechanisms in physiopathology of spinal cord ischemic edema.
authors.affiliation: Department of Orthopaedics, Dalian Municipal Central Hospital, Da Lian 116033, Liaoning Province, PR China.
authors.forename: Wei-bing
authors.initials: WB
authors.lastname: Xu
authors.forename: Yan-ting
authors.initials: YT
authors.lastname: Gu
authors.forename: Yan-feng
authors.initials: YF
authors.lastname: Wang
authors.forename: Xu-hua
authors.initials: XH
authors.lastname: Lu
authors.forename: Lian-shun
authors.initials: LS
authors.lastname: Jia
authors.forename: Gang
authors.initials: G
authors.lastname: Lv
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D051401:Aquaporin 4 / Q000378:metabolism*; D015153:Blotting, Western; D001920:Bradykinin / Q000494:pharmacology*; D004195:Disease Models, Animal; D015870:Gene Expression; D007150:Immunohistochemistry; D007511:Ischemia / Q000378:metabolism*; D008854:Microscopy, Electron; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000098:blood supply* / Q000378:metabolism*; D013119:Spinal Cord Injuries / Q000378:metabolism*
chemical_list: D051401:Aquaporin 4; D001920:Bradykinin